SAN FRANCISCO -- Chris Paddack’s effectiveness Tuesday night was enough to enable the Padres to stomach an otherwise bitter 6-5 loss to the San Francisco Giants.

San Diego had defeated the Giants in five of their previous seven meetings. But after Paddack bequeathed a 4-3 lead to the bullpen after five innings, San Francisco rallied for three runs off Trey Wingenter and doomed the Padres to their third loss in a row and fifth in their last seven games. The Padres (33-34) fell below .500 for only the second time this season. They were 23-24 on May 19.

However, if Paddack can sustain the improvements he made against the Giants, which brought him closer to his top form, the Padres might not have to dwell upon mediocrity. At least when he pitches.

Paddack’s pitching line against the Giants looked less than spectacular. He allowed three runs and six hits in five innings. But he was much sharper than he had been in his previous four outings, when he compiled a 1-3 record with a 5.85 ERA. That differed dramatically from the 3-1 mark and 1.55 ERA that he owned after his first seven starts of the season.

• Box score

This time, working at pitcher-friendly Oracle Park, Paddack regained his winning feeling, though the boxscore didn’t say so.

The right-hander, who struck out six and walked one, proclaimed that he succeeded in “getting back to the Chris Paddack that I know I am. Going up there and having that fastball command early. I thought my curveball was really good tonight. I got a few ugly swings, got a few weak ground balls.”

Paddack credited catcher Austin Hedges for helping him stay mentally focused. During his mini-slump, Paddack said, he was “going up there throwing instead of having that intent, like, ‘Good luck. Hit this.’ ... That’s a lot of starting pitchers’ mentality. You got to go up there and tell yourself that it’s me versus you and you’re going to get beat.”

As a result, Paddack liked what he saw when he occasionally glanced at the scoreboard at his velocity readings, which registered 95 mph or higher on his fastball.

“That’s always a confidence booster,” he said.

Paddack nevertheless knew that he must upgrade his game further, particularly with his changeup.

“It was up in the zone,” he said. “It still didn’t have that bite, [that] dropping-off-the-table action that I normally have. But I’m never going to steer away from my changeup. It’s my bread-and-butter. It’s what got me here.”

Yet it was a fastball that betrayed Paddack the most and possibly prevented him from blanking the Giants. With two outs in the fourth inning and Pablo Sandoval on third base, Tyler Austin drilled an RBI single on a 95.7 mph, full-count fastball. Steven Duggar followed with a home run.

“I’d take one pitch back and that would be to Austin,” Paddack said. “Got him 0-2, two outs, runner on third. I kept throwing heaters, and I think if we go changeup there, he swings over the top of it or we get a weaker ground ball. He squared up that fastball pretty well.”

Paddack was involved in a more pleasant offensive highlight. He collected his first Major League hit, a fifth-inning infield single.

“It’s going to go in my man cave one of these days,” he said.

The evening’s other redeeming factor from the Padres’ perspective was the performance of Fernando Tatis Jr.. He christened the game with a home run off Giants starter Tyler Beede, then raced from second base to score on Eric Hosmer’s fifth-inning infield single.

Tatis crossed the plate with a headfirst slide that was as graceful as it was forceful. It was the kind of effort that the Padres will trumpet when Rookie of the Year balloting comes around later this year.

“I doubt there’s another guy in the game who scores right there,” Padres manager Andy Green said of Tatis’ fifth-inning play. “His slide was as good as it could possibly be. He really sparks the club when he does things like that. He’s an incredibly talented athlete.”